SEMICONDUCTOR DEVICE COMPRISING DUAL EPITAXIAL LAYER CONTACT PLUG STRUCTURE AND FABRICATION METHOD THEREOF

摘要

PURPOSE: A semiconductor device comprising a dual epitaxial layer contact plug structure and a fabrication method thereof are provided which can suppress a lateral overgrowth of an epi layer effectively during a process of forming the epitaxial layer with a selective epitaxial growth method on a revealed silicon layer. CONSTITUTION: The semiconductor device includes a silicon substrate(20), and a word line(23) which is formed on the silicon substrate and whose upper part and sidewall are covered with an insulation film, and a contact plug(29) comprising an SiGe epitaxial layer(26) and an Si epitaxial layer(27) stacked on the silicon substrate between the word line. The SiGe epitaxial layer is formed by a selective epitaxial growth method on the revealed silicon substrate. An insulation film pattern and an insulation film spacer(25) are formed on the upper part and the sidewall of the word line respectively. The SiGe epitaxial layer is formed on the silicon substrate on the revealed silicon substrate between the insulation film spacer by the selective epitaxial growth method. And a cleaning process is performed to remove a hydrocarbon film and an oxide remaining on the silicon substrate.